1. Field of the Invention
The present invention relates to a communication system for providing multimedia services and a communication control method of controlling the same.
2. Description of the Related Art
The developments of electronic equipment, computer technology and communication technology in recent years enable us to transfer various media, including not only sounds but also images (video and still images) and data, among terminals. Multimedia services can now be provided for allowing us to freely transfer these.
It is needless to say that in order to use various media when attempting to utilize such services, called users must be fully equipped to accept such media. Terminals used by called users may not function to respond to communication requests including a plurality of media. The called users may be equipped with terminal devices capable of dealing with all kinds of media, telephone terminal for processing simply sounds, visual telephone terminals and the like for processing video and still images and sounds or facsimile and telephone sets for processing image information and sounds. Indeed, functions vary in accordance with the kinds of terminal units built up on the called user.
Individual terminals may not be able to process all of the plurality of media contained in the communication request. However, by combining the functions of various terminals, it is possible to deal with the plurality of media contained in such requests.
Conventionally, in such situations, in order to accept the plurality of media contained in the communication requests, it was necessary for users (calling users) sending such communication request to recognize what kinds of media the terminals used by the called users could process and then start a connection request for each terminal. For this reason, it has been difficult to perform predetermined communications due to complexity of preparatory states for practical purposes.
Therefore, in order to utilize various media when attempting to use multimedia services, the terminal units built in the called user must be fully corresponded to the various media.
For conferencing communication by using an audio terminal and a data terminal, there is available a technique disclosed in Japanese Unexamined Patent Publication No. 63-1140, which provides a method of making connections to these terminals when a request for starting conference is made. According to this method, upon receiving a particular number indicating a request for starting conference conducted by combining sounds and data, connections are made to the prefixed audio and data terminals.
Consequently, this method lacks general applicability and thus may not provide a high level of freedom for combined connections.